1 files changed, 139 insertions, 0 deletions
diff --git a/browser/extensions/screenshots/background/selectorLoader.js b/browser/extensions/screenshots/background/selectorLoader.js
new file mode 100644
index 0000000000..347b29deb8
--- /dev/null
+++ b/browser/extensions/screenshots/background/selectorLoader.js
@@ -0,0 +1,139 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* globals browser, catcher, communication, log, main */
+
+"use strict";
+
+// eslint-disable-next-line no-var
+var global = this;
+
+this.selectorLoader = (function() {
+  const exports = {};
+
+  // These modules are loaded in order, first standardScripts and then selectorScripts
+  // The order is important due to dependencies
+  const standardScripts = [
+    "log.js",
+    "catcher.js",
+    "assertIsTrusted.js",
+    "assertIsBlankDocument.js",
+    "blobConverters.js",
+    "background/selectorLoader.js",
+    "selector/callBackground.js",
+    "selector/util.js",
+  ];
+
+  const selectorScripts = [
+    "clipboard.js",
+    "build/selection.js",
+    "build/shot.js",
+    "randomString.js",
+    "domainFromUrl.js",
+    "build/inlineSelectionCss.js",
+    "selector/documentMetadata.js",
+    "selector/ui.js",
+    "selector/shooter.js",
+    "selector/uicontrol.js",
+  ];
+
+  exports.unloadIfLoaded = function(tabId) {
+    return browser.tabs
+      .executeScript(tabId, {
+        code: "this.selectorLoader && this.selectorLoader.unloadModules()",
+        runAt: "document_start",
+      })
+      .then(result => {
+        return result && result[0];
+      });
+  };
+
+  exports.testIfLoaded = function(tabId) {
+    if (loadingTabs.has(tabId)) {
+      return true;
+    }
+    return browser.tabs
+      .executeScript(tabId, {
+        code: "!!this.selectorLoader",
+        runAt: "document_start",
+      })
+      .then(result => {
+        return result && result[0];
+      });
+  };
+
+  const loadingTabs = new Set();
+
+  exports.loadModules = function(tabId) {
+    loadingTabs.add(tabId);
+    catcher.watchPromise(
+      executeModules(tabId, standardScripts.concat(selectorScripts)).then(
+        () => {
+          loadingTabs.delete(tabId);
+        }
+      )
+    );
+  };
+
+  function executeModules(tabId, scripts) {
+    let lastPromise = Promise.resolve(null);
+    scripts.forEach(file => {
+      lastPromise = lastPromise.then(() => {
+        return browser.tabs
+          .executeScript(tabId, {
+            file,
+            runAt: "document_start",
+          })
+          .catch(error => {
+            log.error("error in script:", file, error);
+            error.scriptName = file;
+            throw error;
+          });
+      });
+    });
+    return lastPromise.then(
+      () => {
+        log.debug("finished loading scripts:", scripts.join(" "));
+      },
+      error => {
+        exports.unloadIfLoaded(tabId);
+        catcher.unhandled(error);
+        throw error;
+      }
+    );
+  }
+
+  exports.unloadModules = function() {
+    const watchFunction = catcher.watchFunction;
+    const allScripts = standardScripts.concat(selectorScripts);
+    const moduleNames = allScripts.map(filename =>
+      filename.replace(/^.*\//, "").replace(/\.js$/, "")
+    );
+    moduleNames.reverse();
+    for (const moduleName of moduleNames) {
+      const moduleObj = global[moduleName];
+      if (moduleObj && moduleObj.unload) {
+        try {
+          watchFunction(moduleObj.unload)();
+        } catch (e) {
+          // ignore (watchFunction handles it)
+        }
+      }
+      delete global[moduleName];
+    }
+    return true;
+  };
+
+  exports.toggle = function(tabId) {
+    return exports.unloadIfLoaded(tabId).then(wasLoaded => {
+      if (!wasLoaded) {
+        exports.loadModules(tabId);
+      }
+      return !wasLoaded;
+    });
+  };
+
+  return exports;
+})();
+null;